This invention relates to a cutting tool, and more particularly to a tool for use in reaming an opening in an object.
When recapping or retreading tires, it is desirable to ream an opening in the tire where there has been a puncture in the tire. The opening is reamed to a nominal diameter, and a rubber plug is placed in the reamed opening prior to the recapping or retreading process.
With modern tire construction emphasizing durability of the tire, various reinforcing and/or stablizing materials are incorporated into the tire in a multi-layer fashion. One such material incorporated into tires a steel belt. Reaming openings in steel belted tires is a difficult task and, to date, there has been no satisfactory reaming tools which provide a clean opening in the tire and which can stand a high number of repeated reaming operations in a steel belted tire.
It is an object of the present invention to provide a cutting tool for use in reaming an opening in an object, such as a steel belted tire, which provides an opening having clean sidewalls by shearing off the steel filaments in the steel belt at the opening.
It is a further object of the invention to provide a cutting tool which is capable of withstanding a high number of repeated reaming operations.
It is further an object of the invention to provide a cutting tool which quickly, cleanly and easily cuts through an object, such as a steel belted tire, when mounted to a rotating tool, so as to relieve operator stress and injury.
In accordance with the invention, a tool for use with a rotating device for forming an opening in an object comprises an axial body portion and an end portion. The end portion is adapted to be received within the rotating device so that, upon rotation thereof, rotation is imparted to the tool. The body portion includes a plurality of helical endmill flutes extending from an end of the body portion and oriented at a first angular relationship to the axis of the body portion. A plurality of helical burr flutes are formed at the outer tips of the endmill flutes, and are oriented at an angular relationship relative to the axis of the body portion opposite that of the endmill flutes. The body portion is preferably provided with a sharpened tip opposite the end portion, for easy entry of the tool into the object. The sharpened tip preferably has a plurality of helical flutes formed therein. Each of the flutes in the sharpened tip preferably provides a substantially radially oriented cutting surface which bites into the object during rotation of the tool. In a preferred embodiment, the body portion defines a first diameter upon rotation of the tool, and a neck portion is preferably disposed between the body portion and the end portion, with the neck portion having a reduced diameter relative to that of the body portion. The endmill flutes provide a relatively small number of deep helical grooves about the body portion. The burr flutes provide a relatively large number of shallow grooves extending about the body portion in a helical direction opposite that of the endmill flutes.
The invention also contemplates a method of making a cutting tool, substantially in accordance with the foregoing description. Also contemplated is a method of forming an opening in an object, also in accordance with the foregoing.